[PATCH RESEND] wifi: ath12k: fix MAC address copy on big endian

[Baochen Qiang]

On 7/2/2026 8:06 PM, Alexander Wilhelm wrote:
> On Thu, Jul 02, 2026 at 05:56:01PM +0800, Baochen Qiang wrote:
>>
>>
>> On 7/2/2026 5:17 PM, Alexander Wilhelm wrote:
>>> On Thu, Jul 02, 2026 at 10:41:25AM +0200, Alexander Wilhelm wrote:
>>>> On Thu, Jul 02, 2026 at 04:12:00PM +0800, Baochen Qiang wrote:
>>>>>
>>>>>
>>>>> On 6/29/2026 3:55 PM, Alexander Wilhelm wrote:
>>>>>> The ath12k_dp_get_mac_addr function performs a simple memcpy from a
>>>>>> CPU-native data types into an u8 array. On a big-endian architecture, this
>>>>>> later results in a null‑pointer dereference. Convert the data to
>>>>>
>>>>> Alex, did you find a time to investigate the root cause of the null pointer?
>>>
>>> Hi Baochen,
>>>
>>> I am now running kernel v6.18.26, and it looks like the null-pointer issue is
>>> gone. I only see the following log messages:
>>>
>>>     ath12k_pci 0001:01:00.0: failed to vdev 0 create peer for AP: -110
>>
>> what is the actual mac addr reported from firmware in the PEER MAP event? My understanding
>> is that, without this patch (if we really need it) we get a wrong mac addr, then in
>> ath12k_dp_link_peer_map_event() we are more likely to fail the peer look up hence would
>> create a new peer and wakeup the waiting thread. But the log here clearly indicates that
>> the wait timeout, which does not make sense to me.

I think I can understand the behavior here: even if wakeup happens, the waiter in
ath12k_wait_for_dp_link_peer_common() checks the map result by calling
ath12k_dp_link_peer_find_by_vdev_and_addr(). Since the mac addr of the newly created peer
does not match, check failed. Finally we get timeout.

> 
> I have now added the following debug output for `peer_map_ev` inside of
> `ath12k_dp_htt_htc_t2h_msg_handler`:
> 
>     /* DEBUG */
>     switch (type) {
>     case HTT_T2H_MSG_TYPE_PEER_MAP:
>     case HTT_T2H_MSG_TYPE_PEER_MAP2:
>     case HTT_T2H_MSG_TYPE_PEER_MAP3:
>         ath12k_err(ab, "[DEBUG]: resp->peer_map_ev.info: %08X\n", le32_to_cpu(resp->peer_map_ev.info));
>         ath12k_err(ab, "[DEBUG]: resp->peer_map_ev.mac_addr_l32: %08X\n", le32_to_cpu(resp->peer_map_ev.mac_addr_l32));
>         ath12k_err(ab, "[DEBUG]: resp->peer_map_ev.info1: %08X\n", le32_to_cpu(resp->peer_map_ev.info1));
>         ath12k_err(ab, "[DEBUG]: resp->peer_map_ev.info2: %08X\n", le32_to_cpu(resp->peer_map_ev.info2));
>         break;
>     default:
>         break;
>     }
> 
> Here is the result:
> 
>     ath12k_pci 0001:01:00.0: [DEBUG]: resp->peer_map_ev.info: 0002002B
>     ath12k_pci 0001:01:00.0: [DEBUG]: resp->peer_map_ev.mac_addr_l32: C921F004
>     ath12k_pci 0001:01:00.0: [DEBUG]: resp->peer_map_ev.info1: FFFF0EE0
>     ath12k_pci 0001:01:00.0: [DEBUG]: resp->peer_map_ev.info2: 000502F5
>     ath12k_pci 0001:01:00.0: failed to vdev 0 create peer for AP: -110
>     ath12k_pci 0001:01:00.0: failed to create vdev 04:f0:21:c9:e0:0e ret -110
>     ath12k_pci 0001:01:00.0: failed to assign chanctx for vif 04:f0:21:c9:e0:0e link id 0 link vif is already started
>     ath12k_pci 0001:01:00.0: invalid vdev id in vdev delete resp ev 0
> 
> Let me know if you see anything suspicious or if you need additional debug
> information.

I am not really sure about the final mac addr and vdev id passed to
ath12k_dp_link_peer_map_event(), so can you also add print below?

diff --git a/drivers/net/wireless/ath/ath12k/dp_peer.c
b/drivers/net/wireless/ath/ath12k/dp_peer.c
index 47d009a0d61f..3e8201d536a5 100644
--- a/drivers/net/wireless/ath/ath12k/dp_peer.c
+++ b/drivers/net/wireless/ath/ath12k/dp_peer.c
@@ -162,6 +162,9 @@ void ath12k_dp_link_peer_map_event(struct ath12k_base *ab, u8 vdev_id,
u16 peer_
        struct ath12k_dp *dp = ath12k_ab_to_dp(ab);
        struct ath12k *ar;

+       pr_info("peer map event: vdev_id %u peer_id %u mac_addr %pM ast_hash %u hw_peer_id
%u\n",
+               vdev_id, peer_id, mac_addr, ast_hash, hw_peer_id);
+
        spin_lock_bh(&dp->dp_lock);
        peer = ath12k_dp_link_peer_find_by_vdev_and_addr(dp, vdev_id, mac_addr);
        if (!peer) {


> 
> 
> Best regards
> Alexander Wilhelm